The development of animal control measures using electroshocking techniques is of considerable interest. Electrofishing has gained prominence in recent years as a method for the capture and control of fish for research. Electrofishing involves the application of electric power through a volume of water containing fish. It has been determined that the magnitude of the electrical power that is transferred from the water into the fish determines the success or failure of the electrofishing operation. The electroshocking power is supplied from electric generators that produce either a direct current, sinusoidal alternating current, pulsed alternating current, or a pulse direct current into the water. Electroshock to a fish in a body of water can result in different responses including a twitch, an anodic attraction, a stun or complete tetany depending on the magnitude of the induced in-vivo power density.
The electrofishing literature discloses attempts to correlate current and voltage gradient measures in a body of water against the observed electroshock responses of fish. However, there are no known attempts to measure and then relate the significance of electric power density to the electroshock phenomenon.
Peters U.S. Pat. No. 2,625,588 discloses apparatus for measuring potential differences in a liquid body by providing an auxiliary path for the liquid together with a coil coupled to this path which has induced therein electromagnetic forces with the magnitude of these forces being indicative of the electric potential across the liquid.
Rezek U.S. Pat. No. 2,795,759, Medlar U.S. Pat. No. 2,780,781, Rezek U.S. Pat. No. 2,832,046 and Godshalk U.S. Pat. No. 2,802,182 disclose different types of instruments for measuring the density of current in a liquid body using a coil on a core immersed in a liquid bath.
Schainbaum U.S. Pat. No. 3,753,109 discloses a peak detector circuit in a different circuit arrangement.
A publication of the United States Department of the Interior, Fish and Wildlife Service, Technical Report 22 entitled "Electrofishing, A Power Related Phenomenon" of which the inventor of the subject application is an author discusses in detail electrofishing and related technical terminology.